Bright Ideas

Motion Sensors and Lights

One of the most helpful accessories to a light fixture is the motion sensor. These sensors are available in a number of different varieties, but each serves essentially the same purpose: to notice movement in a designated area. This technology is obviously useful in security applications, especially when paired with an alarm system, but it can also add a convenience factor, or a little flair, to your lighting.

Lights With Motion Sensors

The idea behind installing a light with a motion sensor (which can either be part of the fixture or a separate attachment) is pretty simple: you get light when you need it and not when you don’t. The motion sensor understands when someone is in the space that needs to be lit, communicates with the light fixture, and there you have it – a more convenient, environmentally-conscious lighting solution.

Motion Sensors with Photocells

To take motion sensor functionality to the next level, consider one that also has a built in photocell. This way, in addition to being able to respond to motion, the sensor is also sensitive to light. The benefit? Moving around with sunlight pouring through the windows won’t set off your lights. You never have to remember to turn them on (or off), and you can trust that they will not consume excessive electricity unless they’re needed (ultimately saving you money).

Where to Put Them

Indoor Applications:

A few, properly placed motion sensors can really change the utility and security of a space. Motion sensors used for tasks (such as turning a light on at a desk) can be placed near the area of motion, to detect specific movement. For larger areas, sensors should be placed so that they have an expansive, unimpeded view of the space. Think of placing it higher up on the wall, or in a corner, to maximize the sensor’s “field of vision”. However, keep in mind both the radius and reach of a sensor's detection capability. Placing it too high or too far across a wall will create dead zones, which would be incovenient for working areas, such as a conferences room or a classrooms, or risky in high-security locations. Think about which areas of the room will be used, and try to have them covered by one or a combination of sensors.

Outdoor Applications:

And here's something else to consider: while a motion sensor with the highest range and greatest degree of detection may seem like the best quality sensor on the market, it may not be the one that will work the best for you. For example, if you share a driveway with a neighbour, and don't want movement on their side to trigger your lights, a 180 degree sensing light may not be the best decision. The motion sensor you pick should match the space you're trying to light.

To know what range capabilities your motion sensor has, take a look at its specifications sheet. One of ours, for example, looks like this:

With a 240 degree range, it's not suited for shared driveways, but it's ideal for corners and backyards.

Also, make sure that the sensor has a good view of points of entry. In addition to main entrances, consider monitoring back doors, basement entries, and upper level access points, especially if security is a concern for your building. If you’re looking to install a motion-activated light fixture outside, check to see if the sensor can handle the weather in your area.

Generally, motion sensors are better at detecting movement from side-to-side than head on. Instead of directly facing a door or hallway, consider placing the sensor parallel to the area of movement – on one side of the door, or the side wall of a main walkway.

Where Not to Put Them

How you place your sensors is more important than how many sensors you put up. There are some areas where installing sensors could actually be counterproductive.

One such area is directly across a window, especially for heat-sensitive motion sensors. The sunlight coming in through the window could trick the sensor into thinking someone is on the premises, which will result in unnecessary operation of the light. For similar reasons, keeping the sensor near air vents or heat sources can also lead to faulty readings from the sensors. While a light turning on by accident isn’t the biggest deal, if the light is connected to a larger security system, false positive results could cause undue alarm.